The feminine phantasm can then take entire possession of the pneumatic system of the lover, producing—unless desire finds its natural outlet—somatic disturbances of a quite vexing sort. Called ishq, this syndrom of love is described by Avicenna, whose Liber canonis was the manual of medicine in use in the early Christian Middle Ages. But previously, Constantine the African had spoken of it in his translation of the Liber regius of ‘Ali ibn al-‘Abbas al-Majusi, called Haly Abbas. After Constantine, the semiology of the pathological Eros is described by Arnaldus of Villanova and by Vincent of Beauvais, who classify it among the varieties of melancholia.

The name of the syndrome is amor hereos or, Latinized, heroycus, as its etymology is still in doubt: it might be derived from the Greek erōs, corrupted herōs (love), or directly from herōs (hero), for heroes represented, according to ancient tradition, evil ærial influences, similar to devils.